Thanks Mal. I'll try a rollerball next.
The ballpoint is actually harder than the rollerball, in my opinion.
That's because you have to take into account the range of movement of the refill and the right room for spring compression.
(Of course, in the style of ballpoint you have done, you have left out the movement of the refill, so it's easier ..... THIS time. !! )
You don't have those two considerations for a rollerball.
After the rollerball, the FP is straightforward. . The only extra is making sure you don't "bottom out" on the nib tip and "b***er" it up.
Oh .... and the extra section threading operation, but that is pretty easy after having done some cap threadings already.
It depends on whether you make your own section, or use a nib with ready-made section. . The latter is easier of course and good for 1st time.